2020-2021 ICPC East Central North America Regional Contest (ECNA 2020)
12 problems from 2020-2021 ICPC East Central North America Regional Contest (ECNA 2020) (contest 104587), difficulty -. 12/12 solutions verified against sample I/O.
2020-2021 ICPC East Central North America Regional Contest (ECNA 2020)
ICPC/IOI | 12 problems | 12/12 verified | Difficulty - | 10m 47s
| # | Problem | Rating | Tags | Accepted | Time | ✓ |
|---|---|---|---|---|---|---|
| A | All in the Family | 1m 7s | ✓ | |||
| B | Kinky Word Searches | 55s | ✓ | |||
| C | Math Trade | 46s | ✓ | |||
| D | Oreperations Research | 48s | ✓ | |||
| E | Over the Hill, Part 1 | 48s | ✓ | |||
| F | Over the Hill, Part 2 | 1m 1s | ✓ | |||
| G | A Rank Problem | 43s | ✓ | |||
| H | Restroom Monitor | 47s | ✓ | |||
| I | Scholar's Lawn | 53s | ✓ | |||
| J | Simply Sudoku | 53s | ✓ | |||
| K | Weighty Tomes | 58s | ✓ | |||
| L | Workers of the World Unite! Just Not Too Close. | 1m 8s | ✓ |
CF 104587L - Workers of the World Unite! Just Not Too Close.
We are assigning each worker a route that consists of two independent choices: a gate in the middle layer and a workstation in the final layer. Every worker starts at their own position, enters exactly one gate, and then exits through the same gate to reach a workstation.
CF 104587K - Weighty Tomes
We are given a storage scenario that is mathematically identical to a threshold-finding experiment. There is an unknown limit $x$ such that stacking up to $x$ identical boxes on a pallet is safe, but stacking $x+1$ boxes causes failure.
CF 104587J - Simply Sudoku
We are given a standard 9 by 9 Sudoku grid. Some cells already contain digits from 1 to 9, while empty cells are represented by zeros.
CF 104587I - Scholar's Lawn
We are given a collection of straight walkways drawn on a plane. Each walkway is a finite line segment, and students are only allowed to move along these segments, never through open grass.
CF 104587H - Restroom Monitor
We are given a stream of people who need to be placed into identical single-stall restrooms, where each person occupies a stall for exactly one unit of time. There are s stalls, meaning that at any moment up to s people can be inside simultaneously.
CF 104587G - A Rank Problem
We maintain an evolving ranking of teams labeled $T1$ through $Tn$. Initially, the ranking is fixed in increasing index order, so $T1$ is first and $Tn$ is last. Then we process a sequence of match results, where each result states that one team beats another.
CF 104587F - Over the Hill, Part 2
We are given a classical linear encryption model where fixed-size blocks of text are transformed by multiplying them with an unknown square matrix.
CF 104587E - Over the Hill, Part 1
We are given a fixed alphabet of 37 characters consisting of uppercase English letters, digits, and the space character.
CF 104587D - Oreperations Research
The system consists of three synchronized streams that interact only through a single active “loading position.” One stream is a line of train cars, each with a fixed required capacity.
CF 104587A - All in the Family
We are given a rooted family structure described indirectly through parent-to-children listings, and we must answer queries about how two people are related in genealogical terms.
CF 104587B - Kinky Word Searches
We are given a very small grid of uppercase letters, at most 10 by 10, and we want to know whether a given word can be traced on this grid by walking from cell to cell. The walk starts from any cell and moves in straight line steps on adjacent cells.
CF 104587C - Math Trade
Each person in the input owns exactly one object and wants exactly one object. We can think of each person as a directed edge in a graph: from the object they currently have to the object they want.